1. Field of the Invention
This invention relates to aviation, specifically to flight data recording systems as applied to light aircraft.
2. Description of Prior Art
Most flight data recorders are designed for use in accident investigation in large aircraft such as wide-body airline jets. These are highly expensive systems that consist of several heavy and bulky pieces of equipment and a multitude of sensors and cables deployed throughout the aircraft, making it impractical for use in light aircraft. Recorded data is retrieved by attaching a portable device to the recorder or by physically removing the recorder and bringing it to a retrieval facility. They are designed to withstand very high temperatures for prolonged periods, great impact forces and deep submersion in water. These are the usual environmental conditions present during a violent crash of large aircraft, especially jets. In light aircraft crashes, especially for propeller-driven types, the magnitude of the impact forces are much less and the probability of prolonged and high-intensity fires is less.
State-of-the-art flight data recorders consist of solid state circuits, including the main data storage where data are all recorded in digital format. They normally conform certain international standards such as FAA's TSO C124a, EUROCAE ED-55 and RTCA/DO-178B.
U.S. Pat. No. 6,148,179 issued to Wright, et al. discloses a flight and engine event recording system with a wireless spread spectrum link to a ground station. This is an event-driven system that records only significant changes in flight data and is primarily used for better control of jet engines during take-offs and landings.
U.S. Pat. No. 4,409,670 to Herndon, et al. describes a solid state digital flight data recorder that stores data using a first-in-first-out method and two levels of non-volatile memories. The scope of this invention scope is limited to data storage functions.
U.S. Pat. No. 6,173,159 to Wright et al. is a system for updating flight management files using a wireless spread spectrum data link to ground. It is primarily designed to be used by airlines to update their navigation database files every 28 days using a wireless communications link. Various related patents to the same party deal mostly with different features of a wireless data communications system between aircraft and ground.
U.S. Pat. No. 6,092,008 to Bateman discloses a flight event recording system that records data when it exceeds certain thresholds and allows wireless retrieval of data in real-time. It is designed primarily for accident applications and uses cellular phone technology for wireless communications. The system consists of several modules and sensors distributed throughout the aircraft.
U.S. Pat. No. 5,890,079 to Levine discloses a remote flight monitoring and advisory system that continuously transmits flight data, video and audio to a ground-based monitoring station while the aircraft is in flight. This is more of an on-line monitoring system than a flight data recorder. It requires an expensive communications infrastructure that should guarantee global coverage and this may be difficult to realize.
U.S. Pat. No. 5,283,643 to Fujimoto describes a flight information recording device for small aircraft that utilizes a video camera, mirrors and opal sensors to capture the movement of the wings and control surfaces and record these in a video tape recorder. It also records the pilot's heartbeat and cockpit audio signals. The invention is difficult to install since it requires a multitude of devices and equipment to be deployed throughout the aircraft, many of them mechanical in nature. It also does not have a provision for a wireless data retrieval system.
U.S. Pat. No. 4,729,102 to Miller, Jr. et al., U.S. Pat. No. 4,656,585 to Stephenson and U.S. Pat. No. 4,470,116 to Ratchford are aircraft data acquisition and recording systems that use various pieces of equipment distributed throughout the aircraft and no capability for wireless data retrieval.
U.S. Pat. No. 4,409,670 to Herndon deals with a serial FIFO memory structure for storing flight data while U.S. Pat. No. 4,378,574 to Stephenson is a digital-tape based storage system. Both patents are confined to storage systems only.
The “high performance flight recorder” covered by U.S. Pat. No. 4,970,648 issued to Capots is a digital recording system with no wireless data retrieval capability and does not incorporate sensing functions.